1. Field of the Invention
This invention relates to a commutator, and more particularly to a flat disk commutator in which a segment is arranged on one end face in axial direction of a boss and in a circumferential direction of the boss, which is effectively employed, for instance, in an "In-Tank Type Fuel Feed Pump" in which a motor is integrated with a pump.
2. Related Art Statement
In general, as a fuel feed pump for feeding a fuel to a vehicle such as an automobile, an "In-Tank Type Fuel Feed Pump" in which a motor is integrated with a pump, which is provided in a fuel tank, has been proposed. In an "In-Tank Type Fuel Feed Pump", a "Flat Disk Type Commutator" is employed as a motor.
One the other hand, an "In-Tank Type Fuel Feed Pump" is generally constructed so that a fuel can be fed from a pump to the outside through a motor housing. In this case, the fuel touches to the commutator of the motor.
By the way, in the case of use of gasohol in which alcohol is mixed with the gasoline as fuel, when copper of the commutator which is used in the motor of the fuel feed pump contacts with the gasohol, the fuel is altered, or the copper is penetrated. Hence, a commutator for gasohol is proposed in, for example, U.S. Pat. No. 5,175,463. In this patent, a protecting portion chip(s) made from carbon is(are) attached, by soldering, to at least one surface contacting a brush in a copper of a base member of a segment (commutator bar). When manufacturing such commutator, a plate solder formed into an end face of a carbon protecting portion chip is prepared, the plate solder is inserted between the carbon protecting portion chip and copper main material, and is soldered therebetween.
However, the above manufacturing method for a commutator as described hereinbefore, the dedicated solder plate which is special form have to be made, so that the manufacturing cost increase.